tcping现有退出码设计不合理

按照Linux命令的设计规范，如果tcping探测一个套接字失败，应该使用异常退出码退出，而非使用正常退出码0退出。例如：

$ tcping -c 1 128.0.0.1 22
Ping tcp://128.0.0.1:22 - failed: dial tcp 128.0.0.1:22: i/o timeout

Ping statistics tcp://128.0.0.1:22
    1 probes sent.
    0 successful, 1 failed. # 命令执行失败
Approximate trip times:
    Minimum = 0s, Maximum = 0s, Average = 0s

$ echo $?
0 # Linux环境下为正常退出码

在此，给出ping命令的退出码示例：

$ ping -c 1 128.0.0.1
PING 128.0.0.1 (128.0.0.1) 56(84) bytes of data.

--- 128.0.0.1 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms # 命令执行失败
$ echo $?
1 # Linux环境下为异常退出码

cloverstd / tcping

tcping现有退出码设计不合理 #34